Robust Control of Active Suspensions

2007 ◽  
Author(s):  
Dongsuk Kum ◽  
Huei Peng
Keyword(s):  
Degrees Of Freedom ◽  
Disturbance Attenuation ◽  
Control Synthesis ◽  
Control Architecture ◽  
Single Input Single Output ◽  
Single Output ◽  
Stability Robustness ◽  
Road Disturbance ◽  
Main Culprit ◽  
Single Input

Active suspension has been widely studied in recent decades but the implementation of the single-input, single-output (SISO) force-control architecture that many of the prior studies use has had limited success due to the lightly damped zeros. The inherent trade-off between robust stability and road disturbance attenuation for SISO control architecture is the main culprit. In this paper, we study whether the single-input, two-output (SITO) control architecture provides sufficient degrees of freedom in the control synthesis. First, a quarter car model with an electromagnetic motor is derived and the improved LQG/LTR design technique is employed to simultaneously recover both stability robustness and disturbance attenuation properties at the expense of measurement noise sensitivity. It was found that if the control system is restricted to SISO architecture, sprung mass acceleration is the most promising choice among practical measurements. Both classical and modern control approaches are used to analyze the effectiveness of the proposed method and its closed-loop performance. Simulation results show that stability robustness and disturbance attenuation can be dramatically improved by the SITO architecture over its SISO counterpart.

Nonlinear State Estimation by Adaptive Embedded RBF Modules

1999 ◽  
Vol 123 (1) ◽  
pp. 44-48 ◽  
Author(s):  
Chengyu Gan ◽  
Kourosh Danai
Keyword(s):  
State Estimation ◽  
Degrees Of Freedom ◽  
Compensation Method ◽  
Estimation Model ◽  
Single Input Single Output ◽  
Single Output ◽  
Nonlinear State Estimation ◽  
Single Input ◽  
Range Of Variation ◽  
Nonlinear State

A modeling compensation method is introduced to enhance the performance of the extended Kalman filter (EKF) in coping with the uncertainty of estimation model. In this method, single-input single-output radial basis function (RBF) modules are embedded within the nonlinear estimation model to provide additional degrees of freedom for model adaptation. The weights of the embedded RBF modules are adapted by the EKF, concurrent with state estimation. This compensation method is tested in application to a benchmark problem. Simulation results indicate that the RBF modules provide the means to model the uncertain components of the estimation model within their range of variation.

Multivariable Loop-Shaping in Bilateral Telemanipulation

2005 ◽  
Vol 128 (3) ◽  
pp. 482-488 ◽  
Author(s):  
Kevin B. Fite ◽  
Michael Goldfarb
Keyword(s):  
Impedance Control ◽  
Singular Values ◽  
Single Input Single Output ◽  
Single Output ◽  
Stability Robustness ◽  
Loop Shaping ◽  
Single Input ◽  
The Stability ◽  
Three Degree Of Freedom ◽  
And Control

This paper presents an architecture and control methodology for obtaining transparency and stability robustness in a multivariable bilateral teleoperator system. The work presented here extends a previously published single-input, single-output approach to accommodate multivariable systems. The extension entails the use of impedance control techniques, which are introduced to render linear the otherwise nonlinear dynamics of the master and slave manipulators, in addition to a diagonalization multivariable loop shaping technique, used to render tractable the multivariable compensator design. A multivariable measure of transparency is proposed based on the relative singular values of the environment and transmitted impedance matrices. The approach is experimentally demonstrated on a three degree-of-freedom scaled telemanipulator pair with a highly coupled environment. Using direct measurement of the power delivered to the operator to assess the system’s stability robustness, along with the proposed measure of multivariable transparency, the loop-shaping compensation is shown to improve the stability robustness by a factor of two and the transparency by more than a factor of five.

scholarly journals Parametric Robust Control of the Multivariable 2 × 2 Looper System in Steel Hot Rolling: A Comparison between Multivariable QFT and H∞

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 839 ◽  
Author(s):  
Luis F. Cantú ◽  
Pedro Mendiola ◽  
Álvaro A. Domínguez ◽  
Alberto Cavazos
Keyword(s):  
Frequency Domain ◽  
Hot Rolling ◽  
Performance Indicators ◽  
Single Input Single Output ◽  
Single Output ◽  
Stability Robustness ◽  
Higher Power ◽  
Single Input ◽  
Hot Rolling Mill ◽  
Looper System

Two robust mutlivariable controllers, H∞ and a decentralized quantitative feedback theory (QFT), are designed in the frequency domain for the 2 × 2 looper system in a steel hot rolling mill to keep stability in the presence of parametric uncertainties. The H∞ controller is designed by using the mixed sensitivity approach, while the multivariable decentralized QFT is designed by the extension of the sequential loop closing method presented elsewhere. Stability robustness conditions are verified in the frequency domain, while simulations in time domain are carried out to evaluate the controllers and compare their performance along with that of proportional + integral (PI) and single input single output (SISO) QFT controllers designed earlier. The QFT controller shows the best balance among the performance indicators analyzed here; however, at the expenses of using higher power in one of the control inputs.

Robust polynomial eigenstructure assignment using dynamic feedback controllers

1997 ◽  
Vol 211 (1) ◽  
pp. 35-51 ◽  
Author(s):  
B A White
Keyword(s):  
Eigenstructure Assignment ◽  
Systematic Design ◽  
Dynamic Feedback ◽  
Feedback Controllers ◽  
Single Input Single Output ◽  
Single Output ◽  
Stability Robustness ◽  
Single Input ◽  
And Performance ◽  
Value Decomposition

This paper presents a dynamic controller format for use in polynomial eigenstructure assignment. It formulates the controller in singular-value decomposition format, which enables the designer to use simple SISO (single-input, single-output) compensators, together with direction matrices to construct the controller. The technique utilizes the root locus to evaluate stability and performance. It also introduces several metrics for decoupling, disturbance rejection, actuator movement and stability robustness in a graphical manner that allows a systematic design to be carried out. The paper also includes a two-input, two-output design example to illustrate the technique.

Comparative analysis of SISO and wavelength diversity-based FSO systems at different transmitter power levels

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Varun Srivastava ◽  
Abhilash Mandloi ◽  
Dhiraj Kumar Patel
Keyword(s):  
Optical Signal ◽  
Free Space Optical ◽  
Optical Source ◽  
Transmit Power ◽  
Single Input Single Output ◽  
Transmitter Power ◽  
Single Output ◽  
Communication Links ◽  
Single Input ◽  
Matching Performance

AbstractFree space optical (FSO) communication refers to a line of sight technology, which comprises optical source and detector to create a link without the use of physical connections. Similar to other wireless communication links, these are severely affected by losses that emerged due to atmospheric turbulence and lead to deteriorated intensity of the optical signal at the receiver. This impairment can be compensated easily by enhancing the transmitter power. However, increasing the transmitter power has some limitations as per radiation regulations. The requirement of high transmit power can be reduced by employing diversity methods. This paper presents, a wavelength-based diversity method with equal gain combining receiver, an effective technique to provide matching performance to single input single output at a comparatively low transmit power.

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